Scientists Create Universal Nasal Spray Vaccine That Protects Against COVID, Flu, and Pneumonia

For decades, scientists have chased the idea of a universal vaccine capable of protecting against virtually any infectious threat. That goal has often seemed almost mythical. Now, researchers at Stanford Medicine report a major step toward that vision. In a new mouse study published February 19 in Science, they developed an experimental universal vaccine that shields against a broad range of respiratory viruses, bacteria, and even allergens. The vaccine is given intranasally — such as through a nasal spray — and provides wide-ranging protection in the lungs that lasts for months. Vaccinated mice were protected from SARS-CoV-2 and other coronaviruses, Staphylococcus aureus and Acinetobacter baumannii (common hospital-acquired infections), as well as house dust mites (a common allergen). 'We were interested in this idea because it sounded a bit outrageous,' said senior author Bali Pulendran, PhD, the Violetta L. Horton Professor II and professor of microbiology and immunology at Stanford. 'I think nobody was seriously entertaining that something like this could ever be possible.' Unlike traditional vaccines that present the immune system with a recognizable piece of a pathogen, this new vaccine imitates the communication signals immune cells exchange during infection. By doing so, it links the body's two main defense systems — innate and adaptive immunity — into a coordinated and longer-lasting response. The challenge with current vaccines is that many pathogens evolve quickly. When viruses change their surface structures, previously effective vaccines lose potency — which is why updated COVID-19 boosters and annual flu shots are necessary. 'Like the proverbial leopard that changes its spots, a virus can change the antigens on its surface,' Pulendran explained. 'It's becoming increasingly clear that many pathogens are able to quickly mutate.' If similar results are achieved in people, a single nasal spray could potentially replace multiple yearly shots for seasonal respiratory illnesses and provide rapid protection if a new pandemic virus emerges. The study's lead author is Haibo Zhang, PhD, a postdoctoral scholar in Pulendran's lab. While human clinical trials are still needed, the breadth of protection seen in mice has exceeded researchers' expectations and opened an entirely new chapter in vaccinology.